using System;
using System.Text;
/*
 * Copyright 2007 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace iTextSharp.text.pdf.qrcode {

    /**
     * <p>Represents a 2D matrix of bits. In function arguments below, and throughout the common
     * module, x is the column position, and y is the row position. The ordering is always x, y.
     * The origin is at the top-left.</p>
     *
     * <p>Internally the bits are represented in a 1-D array of 32-bit ints. However, each row begins
     * with a new int. This is done intentionally so that we can copy out a row into a BitArray very
     * efficiently.</p>
     *
     * <p>The ordering of bits is row-major. Within each int, the least significant bits are used first,
     * meaning they represent lower x values. This is compatible with BitArray's implementation.</p>
     *
     * @author Sean Owen
     * @author dswitkin@google.com (Daniel Switkin)
     */
    public sealed class BitMatrix {

        // TODO: Just like BitArray, these need to be public so ProGuard can inline them.
        public int width;
        public int height;
        public int rowSize;
        public int[] bits;

        // A helper to construct a square matrix.
        public BitMatrix(int dimension) : this(dimension, dimension) {
        }

        public BitMatrix(int width, int height) {
            if (width < 1 || height < 1) {
                throw new ArgumentException("Both dimensions must be greater than 0");
            }
            this.width = width;
            this.height = height;
            int rowSize = width >> 5;
            if ((width & 0x1f) != 0) {
                rowSize++;
            }
            this.rowSize = rowSize;
            bits = new int[rowSize * height];
        }

        /**
         * <p>Gets the requested bit, where true means black.</p>
         *
         * @param x The horizontal component (i.e. which column)
         * @param y The vertical component (i.e. which row)
         * @return value of given bit in matrix
         */
        public bool Get(int x, int y) {
            int offset = y * rowSize + (x >> 5);
            return ((bits[offset] >> (x & 0x1f)) & 1) != 0;
        }

        /**
         * <p>Sets the given bit to true.</p>
         *
         * @param x The horizontal component (i.e. which column)
         * @param y The vertical component (i.e. which row)
         */
        public void Set(int x, int y) {
            int offset = y * rowSize + (x >> 5);
            bits[offset] |= 1 << (x & 0x1f);
        }

        /**
         * <p>Flips the given bit.</p>
         *
         * @param x The horizontal component (i.e. which column)
         * @param y The vertical component (i.e. which row)
         */
        public void Flip(int x, int y) {
            int offset = y * rowSize + (x >> 5);
            bits[offset] ^= 1 << (x & 0x1f);
        }

        /**
         * Clears all bits (sets to false).
         */
        public void Clear() {
            int max = bits.Length;
            for (int i = 0; i < max; i++) {
                bits[i] = 0;
            }
        }

        /**
         * <p>Sets a square region of the bit matrix to true.</p>
         *
         * @param left The horizontal position to begin at (inclusive)
         * @param top The vertical position to begin at (inclusive)
         * @param width The width of the region
         * @param height The height of the region
         */
        public void SetRegion(int left, int top, int width, int height) {
            if (top < 0 || left < 0) {
                throw new ArgumentException("Left and top must be nonnegative");
            }
            if (height < 1 || width < 1) {
                throw new ArgumentException("Height and width must be at least 1");
            }
            int right = left + width;
            int bottom = top + height;
            if (bottom > this.height || right > this.width) {
                throw new ArgumentException("The region must fit inside the matrix");
            }
            for (int y = top; y < bottom; y++) {
                int offset = y * rowSize;
                for (int x = left; x < right; x++) {
                    bits[offset + (x >> 5)] |= 1 << (x & 0x1f);
                }
            }
        }

        /**
         * A fast method to retrieve one row of data from the matrix as a BitArray.
         *
         * @param y The row to retrieve
         * @param row An optional caller-allocated BitArray, will be allocated if null or too small
         * @return The resulting BitArray - this reference should always be used even when passing
         *         your own row
         */
        public BitArray GetRow(int y, BitArray row) {
            if (row == null || row.GetSize() < width) {
                row = new BitArray(width);
            }
            int offset = y * rowSize;
            for (int x = 0; x < rowSize; x++) {
                row.SetBulk(x << 5, bits[offset + x]);
            }
            return row;
        }

        /**
         * @return The width of the matrix
         */
        public int GetWidth() {
            return width;
        }

        /**
         * @return The height of the matrix
         */
        public int GetHeight() {
            return height;
        }

        /**
         * This method is for compatibility with older code. It's only logical to call if the matrix
         * is square, so I'm throwing if that's not the case.
         *
         * @return row/column dimension of this matrix
         */
        public int GetDimension() {
            if (width != height) {
                throw new InvalidOperationException("Can't call GetDimension() on a non-square matrix");
            }
            return width;
        }

        public override String ToString() {
            StringBuilder result = new StringBuilder(height * (width + 1));
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    result.Append(Get(x, y) ? "X " : "  ");
                }
                result.Append('\n');
            }
            return result.ToString();
        }

    }
}